New Features on the Phase Transitions of Behenic Acid Monolayers as Unveiled by 2D-Compressibility Coefficient

• 来源期刊: 中国化学(英文版)
• 年，卷（期）: 2008,（9）
• 页码范围: 1596-1600
• 页数: 5页
• 语种: 英文

摘要

Phase behavior of Langmuir monolayers of behenic acid (BeA) has been examined by two-dimensional compressibility.It was found that phase transitions of BeA could be classified into two distinct categories,named Type-I and Type-II in this work.The former is typified by a positive peak on the compressibility-pressure (β-π)curve,indicating the transition can occur itself in a way of collapse from the initial structure.The latter is characterized by a dropping step on the β-π curve,implying that it cannot happen itself and the driven force is continuous compression.For BeA molecules,compressibility coefficients at the initial and final state are the same,βi=βf,for Type-I phase transition from L2 to L2' state,whilst βi＞βf for Type-II phase transition from L.2' state to S state.